Conventional memory devices, either hard disks or floppy disks, are made from material characterized by magnetism, and thereby with access speed inevitably limited by the control mechanism of their access heads.
Furthermore these conventional memory devices may easily be so affected by environmental conditions such as temperature, humidity, or shocks, that the data stored therein may likely get lost or damaged, raising troubles to users.
Usually limited by structures and storage density (capacity per unit of size), IC memories such as RAM and ROM or the like are not suitable for the applications where both size and capacity as well as reliability shall be elaborate.
Developments of various devices have been tried to solve the above problems, among which a solid state disk based on flash memories is quite significant. Therefore the achievement of an apparatus and method for reliably and rapidly accessing the flash memories are widely expected by related industries, especially the realization of an apparatus and method for detouring a fundamental difference between a flash memory device and a conventional memory device is critically expected for easy application. The fundamental difference is that a flash memory device doesn't work in a way of having the data saved (written) in a memory cell (or unit) therein replaced by new data written in the same cell later, as does a conventional memory device. A flash memory device must be formatted into a plurality of blocks each comprising many data memory units each for writing a piece or a set of data therein for only once. Unless a whole block is cleaned (all the data memory units therein are cleaned), any data memory unit which has already had data saved (or written) therein can no longer be written.